<template>
  <div class="spec-preview">
    <img :src="skuInfo.skuDefaultImg" />
    <div class="event" @mousemove="move"></div>
    <div class="big">
      <!-- 因为放大镜是大图的两倍 遮罩层在大图移动 放大镜要反方向移动 -->
      <img :src="skuInfo.skuDefaultImg" :style="{left: -2*left + 'px',top: -2*top + 'px'}"/>
    </div>
    <div class="mask" :style="{left:left + 'px',top:top + 'px'}"></div>
  </div>
</template>

<script>
import {mapGetters} from 'vuex'
  export default {
    name: "Zoom",
    data() {
      return {
        left:0,
        top:0
      }
    },
    computed:{
      ...mapGetters('detail',['skuInfo'])
    },
    methods: {
      move(e){
        // 100这个数值是mask这个盒子的宽度或是高度的一半 因为要让鼠标在mask的中心点
        let x = e.offsetX - 100;
        x = x < 0 ? 0 : x;
        x = x > 200 ? 200 : x;

        let y = e.offsetY - 100;
        y = y < 0 ? 0 : y;
        y = y > 200 ? 200 : y;
        
        this.left = x;
        this.top = y;
      }
    },
    mounted() {
      this.$eventBus.$on()
    },
  }
</script>

<style lang="less">
  .spec-preview {
    position: relative;
    width: 400px;
    height: 400px;
    border: 1px solid #ccc;

    img {
      width: 100%;
      height: 100%;
    }

    .event {
      width: 100%;
      height: 100%;
      position: absolute;
      top: 0;
      left: 0;
      z-index: 998;
    }

    .mask {
      width: 50%;
      height: 50%;
      background-color: rgba(0, 255, 0, 0.3);
      position: absolute;
      left: 0;
      top: 0;
      display: none;
    }

    .big {
      width: 100%;
      height: 100%;
      position: absolute;
      top: -1px;
      left: 100%;
      border: 1px solid #aaa;
      overflow: hidden;
      z-index: 998;
      display: none;
      background: white;

      img {
        width: 200%;
        max-width: 200%;
        height: 200%;
        position: absolute;
        left: 0;
        top: 0;
      }
    }

    .event:hover~.mask,
    .event:hover~.big {
      display: block;
    }
  }
</style>